What's up with Mec powder bushings

[Song Dog]

Reloading crow loads this year; using 1 /4 oz of 5's & 6's in front of 24.5 gr of 800X for STS hull and 25.0 gr for Win AA hull. Per Mec chart bushing # 36 & # 37 should throw the desired charge. Then measured the charges on a scale and weights were in excess of 28.0 gr for a average of 10 throws. Mec bushing # 33 dropped an average of 24.5 of 800X well with in the specs of PSI. The 28.0 gr if not measured would have exceeded pressures over 11000 PSI.

So don't trust shotgun bushing charts

 

[coopermania]

Yea, That checking powder charges with a scale tends to be in the instruction manual and is common knowledge in the reloading world. Powders tend to change sizes lot to lot and year to year.

 

[byf43]

Yea, That checking powder charges with a scale tends to be in the instruction manual and is common knowledge in the reloading world. Powders tend to change sizes lot to lot and year to year.

^^^This!

Don't take the chart to be 'Gospel'. Check the powder bushing/charge bar against a known accurate scale.


I load a LOT of Red Dot powder. 18 grains, specifically, with 1-1/8 oz of shot.
The MEC #30 bushing that I have threw JUST UNDER 18.0 grains.
A little 'honing' of the bushing throws 18 grains, reliably.


A friend of mine wound up using a #32 bushing to get that charge.

Bushings CAN be manufactured differently, and powder most certainly will change from Lot to Lot.
(I also keep a handful of different powder bushings in my 'kit', just in case I need one.)

 

[Redcobra]

For safetys sake I weigh the 1st, 3rd and 5th charge at the beginning of every loading session. If the weights are consistent, I am good to go until I have to refill the powder hopper. The MEC bushing chart is a VERY rough guide as to powder drops.

 

[Kinbote]

It's much easier to get an adjustable charge bar for a Mec, so you can set it to the exact weight you want. They are on sale at Midway currently.

http://ads.midwayusa.com/find?newcategorydimensionid=15473

 

[shooting again]

Recommend you check the shot charge too. My bars tend to throw 10% light with #8 shot. When I was using some reclaimed shot (for skeet loads) it threw even lighter. I presume that was because the shot didn't pack as tightly since it had some deformations from the first time it went out the barrel.

 

[byf43]

It's much easier to get an adjustable charge bar for a Mec, so you can set it to the exact weight you want. They are on sale at Midway currently.

http://ads.midwayusa.com/find?newcategorydimensionid=15473

When these first came out, I bought one.

IMSHO, the Universal Chargebar is a POS. Never repeatable. Always 'fiddling' with it.

Somebody on one of the old BB sites wanted one, I gave it to him.

A friend of mine recently gave me a MEC "Grabber" (I think.) I opened the bag of goodies, and there sits another Universal Chargebar.

I just can't get away from that _ _it!

 

[Winterborn]

I like the Universal Charge bar, its very consistant for me if you lock it in using the hex screws on the two ends.

 

[sxs]

Reloading crow loads this year; using 1 /4 oz of 5's & 6's in front of 24.5 gr of 800X for STS hull and 25.0 gr for Win AA hull. Per Mec chart bushing # 36 & # 37 should throw the desired charge. Then measured the charges on a scale and weights were in excess of 28.0 gr for a average of 10 throws. Mec bushing # 33 dropped an average of 24.5 of 800X well with in the specs of PSI. The 28.0 gr if not measured would have exceeded pressures over 11000 PSI.

So don't trust shotgun bushing charts

Fortunately you learned without learning the hard way. Good for you for checking charges!

 

[Kinbote]

I've never had any trouble with my Universal charge bar, and it makes things much simpler.

 

[John from MD]

+1 on the Universal Chargebar. The main thing to remember is that you must have a reliable scale for any type of reloading. Charts, bushings and scoops don't know when a powder lot changes.

 

[bigjohn]

I have used a smaller bushing and sanded it bigger to get the desired charge drop